A new study highlights how oysters are affected by increasing noise around them. This has consequences for their survival.
Although oysters do not have ears, they can detect vibrations through hair cells on the outside of their shells. And researchers have discovered that the increasing noise pollution in the oceans do have an impact on them, according to a new study recently published in the PLOS ONE journal.
When exposed to noise, oysters would normally respond by closing their shells. This indicates that they are experiencing stress or feeling threatened. (Happy oysters tend to have their shells open.)
However, by closing their shells, the oysters become unaware of the environmental cues around them, and this has consequences for their survival. For instance, they would be unable to detect natural events like rainfall and thunderstorms, and this may hinder them from detecting the time to spawn.
In addition, if they cannot hear the currents, their biological rhythms may be affected. “To hear the current arriving could prepare them for eating and digesting, possibly as when we hear and smell that somebody is preparing dinner,” said co-author Jean-Charles Massabuau, research director at the French National Center for Scientific Research.
“When they are closed, they can’t eat and they can’t breathe," he added, in an email to Newsweek.
In the study, 32 Pacific oysters were exposed to different noise frequencies from a loudspeaker. It was found that they closed their shells in the presence of low frequencies from 10 and 200 hertz, like those made by cargo ships, wind turbines, seismic research, man-made explosions.
Alternatively, higher pitched sounds like those made by jet skis and small recreational boats did not affect the oysters.
Now, the next step of the research will focus on finding out whether long-term exposure to noise has any negative effect on the oysters.